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Finding the Fourth Proportional to 87.79, 131.70 and 42.13

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Solution

The fourth proportional to 87.79, 131.70 and 42.13 is: 63.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.79 : 131.70 = 42.13 : x
  2. Step 2: Convert to fraction form
    87.79/131.70 = 42.13/x
  3. Step 3: Cross multiply
    87.79x = 131.70 × 42.13
  4. Step 4: Simplify right side
    87.79x = 5,548.52
  5. Step 5: Solve for x
    x = 5,548.52/87.79
  6. Step 6: Final answer
    x = 63.20

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.